The invention is an improvement in a feeding device that comprises a rotary drum for receiving and charging material, e.g. metallic bars and tubes, into the heat treatment chamber of a furnace through a horizontally extending opening in the side of the furnace. The support bed or walking beams of, for example, a walking beam furnace, are highly susceptible to damage caused by the abrupt manner in which the material is charged into the furnace. The invention is directed to the provision of a smooth transition of the material from the charging apparatus or drum to the heat treatment chamber of the furnace.
Briefly stated, the invention is in a device for transferring material from a rotary drum charging apparatus to the support bed of the material within the heat treatment chamber of a furnace. The transfer device comprises a pair of arms which are articulated around an axis that is outside the furnace and parallel with the drum, and which are designated to receive the material supplied by the drum and gently lay it down inside the furnace, e.g. on the walking beams of a walking beam furnace.
According to another aspect of the invention, a retractable stop is located adjacent a material receiving cavity in the drum to maintain the material in the cavity during rotation of the drums and effect a smoother transition of the material to the transfer arms when the stops are retracted to allow movement of the material onto the transfer arms.
According to another variation of the latter described aspect of the invention, the shape of the drum cavity is chosen so that the charging or discharging is performed by sliding of the material on two practically orthogonal planar surfaces, when the material has a rectangular cross-section.
It is important to prevent the escape of heated gas from the furnace, or to prevent cold air from entering the furnace. It has been found advantageous in this regard to utilize the transfer arms as a means of removing material from within the furnace.